Method of forming a rigid steel rack bar for automobile jacks



Jan. 5, 1965 ULM METHOD OF FORMING A RIGID STEEL RACK BAR FOR AUTOMOBILE JACKS Original Filed Dec. 1, 1961 3 Sheets-Sheet 1 INVENTOR l l l l. l I

RUSSELL K. ULM

'll llll'lllnllllll R. K ULM Jan. 5, 1965 METHOD OF FORMING A RIGID STEEL RACK BAR FOR AUTOMOBILE JACKS 5 Sheets-Sheet 2 Original Filed Dec. 1,

INVENTOR K. ULM

' 4Q RUSSELL Jan. 5, 1965 R. K. ULM 3,163,925

METHOD OF FORMING A RIGID STEEL RACK BAR FOR AUTOMOBILE JACKS 3 Sheets-Sheet 3 Original Filed Dec. 1, 1961 Fig'lQ .D V F i an "M,

INVENTOR United States Patent 3 163,925 METHQD or f om/inst; A morn srnnr. RACK BAR FOR AUTGPA-UBILE BACKS Russell K. Ulrn, Butler, Ind, assignor to Universal Tool 8; tanrping Company, Ina, Butler, 12111., a corporation of Indiana Original application Dec. 1, 1951, Ser. No. 156,3?8. Divided and this application Sept. 17, 1962, Ser. No. 224,049

4- Claims. (Cl. 29-1592) This application is a division out of US. Serial No. 156,398, filed December 1, 1961.

This invention relates to improvements in a method of producing an improved rack bar for automobile jacks.

Other objects and advantages of this invention will be apparent during the course of the following detailed description.

In the accompanying drawings, forming a part of this specification, and wherein similar reference characters designate corresponding parts throughout the several views:

FIGURE 1 is a fragmentary front elevation of the improved rack bar for lifting jacks.

FIGURE 2 is a fragmentary longitudinal cross sectional View taken substantially on the line 22 of FIGURE 1.

FIGURE 3 is a diagrammatric view showing how the teeth of the improved rack bar are formed in a wall of the tubular rack bar, and more particularly showing tooth forming rolls and the manner in which they cooperate to form the improved tooth arrangement of the rack bar.

FIGURES 4 to 14 inclusive successively show the progressive steps in manipulating cold flat strip steel stock and shaping it into the improved tubular rack bar.

FIGURE 15 is a cross sectional view taken through a modified form of rack bar.

FIGURE 16 is a fragmentary side elevation of the bar of FIGURE 15. a

FIGURE 17 is a cross sectional view taken through another form of rack bar.

FIGURE 18 is a side elevation of the form of rack bar shown in FIGURE 17.

FIGURE 19 is a fragmentary side elevation of the improved jack structure, partly in section, showing the pawl machanism and improved anti-friction means for supporting the lift housing for easy movement along the rack bar.

FIGURE 20 is a plan view of the jack structure shown in FIGURE 19.

FIGURES 21 and 22 are fragmentary cross sectional views taken substantially on the lines 2121 and 2222 of FIGURE 19, and more particularly showing the rear and front anti-friction members of the left housing adapted to engage the rack bar to facilitate easy movement of the pawl supported lift housing therealong.

In the drawings, wherein for the purpose of illustration is shown a preferred embodiment of the jack and modified forms of the rack bar, the letter A may genera ly designate the jack assemblage which includes a base B, improved rack bar C, and lifting assemblage D.

The base construction B is known in the art, and includes a stamped metal inverted cup-shaped main portion having a body 31 and foot flanges 3.2 surrounding the same. A downwardly depending socket portion 33 'is formed integral with the portion 31. It has a rack bar receiving socket 34 in the lower portion thereof. Spot welded to the upper wall of the portion 31 is a dome 6 Ice 35 provided with an opening 36 therethrough for receiving the lower end of rack bar C.

The rack bar C is formed in a continuous production tube mill out of cold flat strip or ribbon steel stock. The forming rolls operate to first produce the teeth in the stock plate, as shown in FIG. 3, and through successive passes the plate is formed by bending operations to produce a bar of tubular formation, polygonal or trapezoidal in cross section, as shown in FIG. 14.

In the sequence of passes the cold flat strip of steel stock enters the mill and a longitudinal series of teeth 40 are rolled centrally thereof; the rear wall 41 thus being depressed from the plane of the laterally extending flange portions 42 and 43. For standard sized jacks the dimensions of the teeth and the formation thereof are designated in FIG. 4 wherein it is shown that the rear edges 42 of each tooth lies appreciably inwardly of the rear surfaces 44 of the side flanges 42 and 43. The sides 46 and 47 are sloped relatively inward towards the rear wall 41 in convergent relation from their curved connections with the flanges 42 and 43. Some of the material from the ribbon of steel is used in forming the indented teeth and that is the reason the wall 41 and side convergent portions 46 and 47 are thinner than the flanges 42 and 43. Referring further to formation of the teeth as shown in FIG. 2 and FIG. 3. The lower pawl engaging portion 50 of each tooth slopes off horizontal downwardly to the rear, and joints with a lower tooth portion 51 which is longer than the portion 50 and which slopes downwardly and to the front; the lower end thereof being connected to the front end of the upper portion 50 of the next lowermost tooth 40. The front wall surface of the tooth portion 51 lies in a plane 30 off vertical and the planes of the outer surfaces of the upper portion 50 and the lower portion 51 of each tooth lie at 90 with respect to each other. The apex of the tooth designated at 52 is convexly curved and from such apex to apex, adjacent teeth extend approximately of an inch. These dimensions may vary somewhat according to the size of rack bar needed. The juncture of theupper face of the tooth portion 50 and the rear face of the portion 51 forms a right angled chisel edge, since the pawls of the jack mechanism are intended to engage in the recess made by the tooth portions 50 and 51, at this juncture.

It will be noted, from FIG. 3 how the bar teeth are rolled; the rolls 60 and 61 being shaped to provide the necessary above described tooth formation, and particularly the chisel edge 63 formed at the juncture of the outer surfaces of the tooth portions 50 and 51.

In the second pass of the rolling mill designated at FIG. 5 the steel ribbon flanges 42 and 43 are provided with longitudinally extending ribs 64, a pair being provided in each flange, although this may vary according to the size of the jack bar, and the ends of these flanges 42 and 43 are upturned in the same direction as indentation of the teeth; the convexed sides of the rib 64 extending also in the same direction as indentation of teeth in the plate.

A third operation as shown in FIG. 6 further curls the portions 65 as'indicated at 65 in FIG. 6.

In FIG. 7 the mill starts the closing operations of flanges 42 and 43 by bending the same at 66. In operations shown in FIGS. 8, 9, 10, 11, 12 and 13, side wall portions of the tube are formed by a sequence of passes through the angles designated in the drawings, and finally the ends of the portion 65 are brought into contact and pass through a welder of the mill where their marginal portions are heated and fused together to provide a front wall 65 designated in FIG. 14. In this view it is shown that in addition to the rear wall 41 there are now provided side walls 70 and 71. At each side of the tooth formation the rack bar is provided with convexly formed trackways 72 which project outwardly beyond the front edges 42 of the teeth. These trackways receive anti-friction means to facilitate sliding'the jack lifting structures along the rack bar.

It will be noted that the distance X (1 16.13) shows that the front edges 42* of teeth 40 are spaced from the rear edges of trackways 72, and the distance Y shows the actual depth of each tooth 40.

Referring now to the lifting assemblage D, the same includes a casing preferably shaped from a single piece of material to provide a central portion 80 having side walls to define a passageway 81 for receiving the bar C; an extension 82 which may appropriately be termed a lifting foot, at the front of the jack, and at the rear of the jack a housing portion 83 for receiving the pawl mechanism. At the lower front corner the casing of the assemblage D has side walls provided with a cross pin 85, shown in FIG. 19 and FIG. 22 adapted to support an anti-friction device 86, detailed in FIGS. 21 and 22, and adapted to operate as an anti-friction piece against the front wall 65* of the jack bar C. This anti-friction member comprises a metal U-shaped clip having leg portions 88 and 89 and a bight portion 90; the leg portions 88 and 89 being apertured to receive the pin 85 upon which the clip swivels. The bight portion has secured thereto a solid synthetic resin anti-friction member 92. The outer surface of which is longitudinally grooved for receiving the wall 65* of the rack bar C as shown in FIG. 22.

At its upper rear corner the housing structure of the lifting assemblage D supports a synthetic resin anti-friction device which is secured in place between the walls of the rack bar receiving portion 89 of the casing and mounted upon a pin 101 supported by said walls, as shown in FIG. 21. This anti-friction device comprises a body portion provided on its front face with raised portions 104 and 105 with concavely curved faces adapted to receive the trackways 72 of the jack bar. The pin 191 holds the anti-friction device shown in FIG. 21 against the rack bar.

The pawl mechanism 120 of the jack structure is conventional and operates for the most part as set forth in abandoned application Serial No. 712,375, filed January 31, 1958. It includes a pawl actuating member 121 The jack lifting assemblage moves upwardly when the handle is moved downwardly and when the handle is rotated upwardly the long pawl is pulled upwardly to the ext tooth 4t} upon the rack bar when the lever 130 is in the position shown in FIG. 19.

As shown in FIGS. and 16, it is proposed to provide a rack bar C'for small sized jacks for use in connection with compact vehicles, which includes all the features above described for the bar C except that this bar C is provided with a single reinforcing rib 64 on each side wall thereof.

As shown in FIGS. 17 and 18, a small sized jack bar C may be provided in which the side walls 70 and 71 7 are angled at 140 instead of being ribbed.

which is a handle receiving socket, pivoted at 122. A

short pawl 123 is provided at 1222 upon the member 121. It is adapted to act upon the rack teeth 40 of the bar C. Upon the member 121 is also pivoted a longer pawl 125, at 126, also adapted to act against the rack teeth 40. A loop shaped spring 127 is provided in the housing structure for the assemblage D connected at one end at 128 to the lower end of the pawl 125 and connected at its other end at 129 to the lower end of the shorter pawl. The function of this spring is to urge the free ends of the pawls into association with respect to the rack teeth of the bar C. A trip lever 130 is pivoted at 131 on the housing of the jack for engagement with the bight portion of the spring 127. When in the position shown in FIG. 19 the spring induces a compressive force large enough to overcome both the tensile and compressive forces introduced in the spring by the alternate up and downward movement of. the long pawl 125. When the trip lever 130 is lifted out of operation the up and downward movement of the handle of the jack and the member 121 will result in the jack descending upon the rack bar C. In operation the short pawl 123 will engage the teeth 40 in the edges 63 and the load will be transferred from the short pawl to the long pawl as the handle is depressed.

Various changes in the size, shape and arrangment of parts may be made to the form of invention herein shown and described without departing from the spirit of the invention or scope of the claims.

I claim:

1. The method of forming a rigid steel rack bar for jacks which consists in taking a ribbon of flat steel stock, forming centrally along said ribbon longitudinally thereof a series of indented teeth with side flanges protruding beyond the outermost edges of said teeth, subsequently bending the stock laterally of said teeth to provide trackways facing in the same direction as the teeth and which trackways protrude substantially beyond the outermost edges of said teeth, and subsequently bending the ribbon into a tube of polygonal cross section and Welding the outermost edges of said strip together.

2. The method of forming a rigid steel rack bar for automobile jacks which consists in taking a ribbon of flat steel stock, die forming centrally along said ribbon and longitudinally thereof a series of indented teeth and a channel in which the teeth are completely countersunk, said teeth and channel lying entirely inwardly of the longitudinal edges of the steel stock, the stock having at each side of said teeth wide side flanges which lie in the same plane, subsequently providing on said side flanges while in flattened condition reinforcing ribs longitudinally thereon, bending the extreme marginal portions of said side flanges to provide narrow marginal flanges, and then in a series of die forming and bending steps moving said side flanges closer together on turning lines at each side of the channel until the proximate outer edges of said marginal flanges are brought into contact and there welding said outer edges of the marginal flanges together.

3. The method of forming av rigid steel rack bar for jacks which consists in taking a ribbon of flat steel stock and die forming a narrow central portion longitudinally thereof into a definite channel extending longitudinally of the stock with transverse teeth arranged longitudinally along said channel with Wide side flanges being thus formed at each side of the central portion, the teeth being entirely inset from the side flange portions of said ribhon ofstock, die shaping said flange portions through a series of angling operations which bend said side flanges at their junctures with the central portion to provide traclrways protruding beyond the outer edges of said in-.

set teeth, the outermost surfaces of the trackways being convened, subsequently bending said side flanges into a polygonal shaped cross sectional structure, and then welding the edges of the stock to form a unitary rack bar.

4. The method of forming a rigid steel rack bar for automobiile jacks which consists in passing a fiat elongtaed strip of steel stock through a rolling mill and forming centrally along the stock a definite channel in which a wall is provided entirely inset from the side longitudinal portions of the stock, said channel being so formed as to provide a series of indented teeth in said channel which are completely countersunk and lie entirely inwardly of the side portions of the stock, said teeth each being formed to provide a shorter upperportion which lies at any angle of 60 to the plane of the stock and a lower sloping longer portion the outer surface of which lies at an angle of ing the forming operation so as to lie entirely inwardly of the outer surfacing of said stock, subsequently bending the stock laterally of said teeth to provide trackways facing in the same direction as the teeth and which trackways protrude substantially beyond the outermost convexed edging of said teeth, said trackways in cross section being thus outwardly convexed during formation, and subsequently bending the stock into a tube of polygonal cross section and Welding the outermost edges of the stock together.

References fitted by the Examiner UNITED STATES PATENTS Durell 29-534 Schmidt 29159.2 X

Taylor- 153-77 X Schmidt et al. 254-111 Riemenschneider 29477.7 X

Ward 74-575 WHITMORE A. VVILTZ, Primary Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,163fl925 January 5 1965 Russell Kg Ulm It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

column 1, line 25 for "diagrammatric" read diagrammatic line 43 for "machanism read mechanism column 3,

line 53., for "provided" read pivoted column 4 line" 65 for "automobiile" read automobile lines 65 and 66 for "elongtaed" read elongated Signed and sealed this 4th day of May 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER Attcsting Officer Commissioner of Patents 

1. THE METHOD OF FORMING A RIGID STEEL RACK BAR FOR JACKS WHICH CONSISTS IN TAKING A RIBBON OF FLAT STEEL STOCK, FORMING CENTRALLY ALONG SAID RIBBON LONGITUDINALLY THEREOF A SERIES OF INDENTED TEETH WITH SIDE FLANGES PROTRUDING BEYOND THE OUTERMOST EDGES OF SAID TETH, SUBSEQUENTLY BENDING THE STOCK LATERALLY OF SAID TEETH TO PROVIDE TRACKWAYS FACING IN THE SAME DIRECTION AS THE TEETH AND WHICH TRACKWAYS PROTRUDE SUBSTANTIALLY BEYOND THE OUTERMOST EDGES OF SAID TEETH, AND SUBSEQUENTLY BENDING THE RIBBON 